Objective:The objective of the study was to determine the efficacy and safety of flexible ureteroscopy (F-URS) for the management of intrarenal or proximal ureteral lithiasis in aged patients.Materials and methods: In this retrospective, multicenter observational study, we collected the anonymized clinical data of patients who underwent F-URS at two institutions in Cali, Colombia between June 2015 and May 2018.The patients were divided into two groups based on age: Group A defined as aged patients (> 65 years) and Group B as patients of non-advanced age (< 65 years).Results: A total of 201 patients were included in this study.The average age for Group A was 75 years (± 4.5) and for Group B was 51 years (± 10).The anesthetic risk classification (American Society of Anesthesiology [ASA]) and comorbidities were significantly higher for Group A with an ASA II and III of 74% versus 50% in Group B. No significant differences were shown in the stone-free rates (SFRs) or significant ureteral injury (Grade III and IV).There was no difference in intraoperative or post-operative complications between both groups.Conclusions: Age > 65 years was not associated with a negative impact on the outcomes of F-URS for the management of intrarenal or proximal ureteral lithiasis in this cohort of patients.F-URS appears as a safe and effective procedure and should not be withheld from older patients.